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Posted By: rowd GFI question - 10/13/02 05:57 PM
I recently wired a kitchen and picked up the outlets, garbage disposal, dishwasher and a light on the downstream. Everything was fine until I turned on the light. Kept tripping the GFI out and I could not find anything wrong with the light. Anyone know why this is happening?
Posted By: sparky66wv Re: GFI question - 10/13/02 06:19 PM
First, A GFCI will trip if there is an unbalance of 6mA or more between the grounded conductor and the ungrounded conductor. Look for any place that the "ground wire" (bare wire) is touching a "neutral", (terminal or bare wire end) such as in the receptacle boxes. Even if the problem is not in the light, it will trip when the light switch is turned on (or any other load) do to the parallel path for the neutral current.

Second, in new wiring, one should not combine lighting, fixed appliances, and small appliance receptacle circuits.

See: 210.52(B)(1) & 210.52(B)(2)

Do not confuse 220.16(A) as permission to combine the small appliance circuits with the lighting loads, this is for demand calcs only!

[This message has been edited by sparky66wv (edited 10-13-2002).]
Posted By: rowd Re: GFI question - 10/13/02 06:48 PM
there is no bare wire. the wiring is in conduit......but if I read you correctly,.... if the neutral is in contact anywhere with the conduit or box the GFI will trip when a load is applied?
Posted By: sparky66wv Re: GFI question - 10/13/02 08:41 PM
In fact, a ground to neutral contact anywhere on that entire circuit (post GFCI) could be causing the problem.

Sorry to assume you were using romex... Pipe? Are you in Chicago? Just curious.

Again, I'm assuming this is residential...

If this is commercial, then 210.52(B)1 & 2 don't apply, and I'm out of line...

[Linked Image]
Posted By: rowd Re: GFI question - 10/14/02 12:12 AM
Yep.... [Linked Image] the Windy City. 6 flat residential on the south side called Hyde Park. All pipe and #12 stranded. I'll have to check the rest of the system for a stray thread of copper touching the ground.....I'm sure that's the problem.
You know how you slide the insulation back and leave it on the end of the wire to keep the ends from fraying out all over the place?
I'd bet dollars to donuts there is a stray strand of copper touching the box somewhere.

[This message has been edited by rowd (edited 10-13-2002).]
Posted By: scjohn Re: GFI question - 10/14/02 12:15 AM
Rowd, this is off the subject, but wiring a house in emt. How long does it take you to wire a 2000 sq. house?? Dont get me wrong, i believe it to be the best way but..
I have always thought that romex was nothing more than glorified extension cord. The few houses that i wire seem to take forever even with 'exstension cord'.
John
Posted By: Electricmanscott Re: GFI question - 10/14/02 12:21 AM
Aren't you not supposed to connect stranded wire to terminals? And why are the lights and appliances being feed from the small appliance circuits? This dosent look too good here.
Posted By: rowd Re: GFI question - 10/14/02 12:21 AM
John.....2000 Sq. Ft.? If it's just me and a helper 10 days.10 to install the pipe and a day to pull it all. Another day to make up all the connections and install devices. But I'm not the fastest pipe bender. [Linked Image] If it's a gang of 4 or "bunker busters" I've seen em do it in three days,......but everything spiders out of ceiling boxes in each room (the quickest) and I wouldn't bet my pay on the square and plumb of the piping job or 1900 bxs.

[This message has been edited by rowd (edited 10-13-2002).]
Posted By: rowd Re: GFI question - 10/14/02 12:38 AM
Quote
Aren't you not supposed to connect stranded wire to terminals? And why are the lights and appliances being feed from the small appliance circuits? This dosent look too good here.

I've never heard of not connecting stranded to terminals except in motor applications. Then you should ise crimp connectors or terminals. Appliances and countertop receptacles can share a circuit as long as you don't have more that two major appliances on a circuit and in Chicago as long as the dishwasher is installed with a counter-top switch to shut off the power to the dishwasher. The one lite that is on the circuit is over the sink.....I don't know if this is allowed or not.I know a receptacle for a clock is allowed on this circuit. I've not had a inspector tag me for it.
Posted By: Electricmanscott Re: GFI question - 10/14/02 09:54 PM
I checked it out and it is a Massachusetts amendment that requires the stranded wire to be either soldered or crimp on connectors used for connections to terminals. The samll appliance circuits are for just that "small appliances" says the NEC. I would argue that neither a dishwasher or disposal would fit this description. A light fixture is not allowed to be on this circuit either.
Posted By: Electric Eagle Re: GFI question - 10/15/02 01:07 AM
WOW, having to run residential in pipe! I'm glad we don't have to do that in Georgia. Here a crew of three, sometimes two, can wire 2000 sq ft in a day. What does it cost to wire a small house like that up there?
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